This invention relates to a method for dot matrix printing of images recorded in accordance with a predetermined definition, and to a printer for implementing the method.
Printers of this type, known as electronic printers, print the information provided by a signal generator or an electronic control system either in the form of alphanumerical characters residing in a memory, or in the form of images which reporduce a configuration of signs received directly from the outside, as in facsimile printing systems. The printing is effected in accordance with a row and column grid, and takes place normally by means of a succession of elementary rows, each of which is composed of a certain number of dots. The fundamental parameter of these printers is the print definition, i.e. the number of dots which can be printed per unit of row or column length.
In known printers, the print definition is generally constant, and depends on the design of the printing element, and is a function of the purpose of the printer.
In particular, for alphanumerical printers used as computer peripherals, the common 7.times.5 matrix is used corresponding to a definition of about 2.5 dots/mm, whereas for printers for facsimile apparatus a definition of about 8 dots/mm is used, and in the case of word processors a greater definition is preferred, for example of about 12 dots/mm.
Known printers are generally designed for printing images, for example alphanumerical characters recorded in accordance with a single definition, so that they are unsuitable for connection to different apparatus. Moreover, they are arranged to print the images with the same definition with which they are recorded, so that the print quality is poor in the case of low definition. In a known printer, it has already been proposed to improve the print quality by inserting intermediate dots between the dots of a diagonal line. However, this printer cannot be connected to apparatus in which the images are recorded with different definitions.